Doesn't look like it to me.. I took one to the vet once.. he said it should look like yellow crusty stuff pushing the scale up/out.Their legs also don’t seem irritated, and they aren’t limping or anything.
But some scales allow for the movement of the joints. Those look fairly normal to me.. Noting some folks will even use Crisco.. to suffocate SLM.. since it's also *edible*.

If treating MANY birds.. I would use Ivermectin.. IF SLM were confirmed. For a small flock topical treatment is simple enough.. Coat the legs.. at night, leave covered.. easiest done after dark (on site) to prevent chasing.